1. Field of the Invention
The invention relates to heterojunction field-effect transistors and to methods for making and operating heterojunction field-effect transistors.
2. Discussion of the Related Art
A field-effect transistor (FET) may have a AlxGa(1-x)As/GaAs heterostructure, a gate electrode, and metallic source and drain electrodes. Between the source and drain electrodes, the AlxGa(1-x)As layer may form a mesa-like structure that supports the gate electrode above the source and drain electrodes. The mesa-like structure electrically may isolate the gate electrode from the source and drain electrodes and the heterostructure interface. The edges of the metallic source and drain electrodes may be aligned to edges of the gate electrode to enable good performance.